Diffusion

Note: Sadly, I have noticed that the code of LaTex changes in WordPress. As an example, the text “\textdegree” use to provide the ˚ symbol but now provides ““. As such, please be patient and do not blame me for all editor faults! 🙂 It truly is an experiment in progress and I am dependent upon LaTex and WordPress consistency.

Conclusion: The molar flux of water is greater than sarin. As such, I assume the evaporation of water is greater than sarin. The latter is supported by a relative volatility (water:sarin) that is 12.6 at the specified conditions. Also, the boiling point of sarin is greater than water.

1991 Gulf War Illness

Before I continue, I would like the reader to know that more than 250,000 United States 1991 Gulf War veterans are suffering from 1991 Gulf War Illnesses. The illness can be psychologically and medically debilitating. For more information and to provide support, please please read the December 2012 scientific journal articles that connect chemical weapons to potential cause of illnesses[7;8]. Also, I wrote a post about differing hypotheses and 1991 Gulf War Illness[17].

Actual mathematical properties of a potential drop

Equation:

The base:

The base radius: 2.3 millimeters; The height: 1 millimeter

Drop volume: Double integration in polar coordinates

In polar coordinates

R is a unit disk in the xy plane and one reason I can use polar coordinates.

The moles of sarin evaporated per square centimeter per unit time may be expressed by[1]

Total molar concentration, c

The gas constant “R” will be calculated at standard temperature and pressure, “STP”

Conversion:

Sarin diffusivity in air at 10 deg Celsius and 1 atmosphere[16]

Assume the gas film

Mole fraction Sarin

From[13a]:

Sarin vapor pressure:

Conversion:

Assume no sarin in the air at a distance away from drop,

For a binary system

The sarin flux

Water

The moles of water evaporated per square centimeter per unit time may be expressed by[1]

Total molar concentration, c

As before, the gas constant “R” will be calculated at standard temperature and pressure, “STP”

Conversion:

Water diffusivity in air at 10 deg Celsius and 1 atmosphere[16]

Assume the gas film

Mole fraction of water

From[4]:

Water vapor pressure:

Constants A, B, C[Appendix A;4], T in kelvins, and pressure is in bar

Conversion:

From[2] and relative humidity of 71% (January weather in Iraq)[9]

Partial pressure of water in flowing stream

Relative humidity[2]:

At 283 K, previous equation gave:

For a binary system

Molar flux of water

Conversion:

Molar Flux: Sarin versus water comparison

Sarin:

Water:

Ratio:

Although the above is a simple evaluation based on “diffusion through a stagnant gas film”[1] and not the most rigorous, the ratio makes since because the ratio of vapor pressures at 10 deg Celsius, “relative volatility”[18], is

Per US Department of Energy[19]

“The evaporation of a liquid depends upon its vapor pressure — the higher the vapor pressure at a given temperature the faster the evaporation — other condition being equal.

The higher/lower the boiling point the less/more readily will a liquid evaporate.”[19]